Photographic spotlight having a flash tube and a modeling lamp



Feb. 20, 1951 F. E. CARLSON PHOTOGRAPHI POTLIGHT HAV A FLASHTUBE A MODELING P Filed July e, 1946 INV'ENTOR: FRANK E. CARLSON, BY Maw- HIS ATTORNEY Patented Feb. 20, 1951 UNITED STATES OFFICE 'PHOTOGRA'PHIC SPOTLIGHT T HAVING. A FLASH TUBEAND A MODELING DAMP- Frank. Qarlson, Cleveland *Heightsg. 0hio,-; as-

signor to General ElectricCompanwa corpora? tion ofNew York Applicationfluly' $11946; serial' Noz 681559 5 lG laims (Cl. 240;-1;3)

My invention relates to light sources and light projecting systemsuparticularly useful. in; photography.

Lamps :emitting a brilliant flash I of actinic radiation and. comprising. a helically coiled. tubula r... envelope for enclosing a luminous'electricdise chargeare coming into extensive .use. fortaking photographs, Such lamps are known aslflashtubes; Thephotographer must pose his subject andfocushis camera before taking the flashlight picture-rand aplamp emittin a. less brilliant but continuous light, such as an incandescent lamp, isgziusually employed for furnishing illumination photographed. By so mounting the different ize luminous elements of thetlamps the illumination from the two. sources:haszapproximately the same distribution.

The above describ'ed arrangement of the luminous elements of the lamps does not lend itself as satisfactorily to spotlighting as it does to flood lighting because the different size luminous elements produce a-greater difference in the candlepower distributions and the spreads of thebeamsi DrQJ'ectedfrom such spotlights. Thus, it: isfdiffi cultfor the photographerto judge where the highlightsand shadows will appearsin thephotograph.

The principal object of my invention is to provide spotlighting equipment for photography comprising a flashtube and a modeling lamp in which the beams produced by the two sources have approximately the same candlepower distribution and spread. Another object of my in vention is to provide such spotlighting equipment capable of producing various lighting effects. Further objects and advantages of the invention will appear from the following detailed description of a species thereof and from the appended claims.

In the drawing accompanying and forming part of the specification an embodiment of m invention is shown in a fragmentary, side-elevational, partly sectional view.

Referring to the drawing the spotlight comprises a flashtube I and. an incandescent lamp 2. Condenser lenses 3 are interposed between the two light sources and a spherical mirror 4 is mounted in back of the incandescent lamp to refiectiincidentzlight backtoward the filament .5. to,; increaseltheclight' traveling toward the lensesiii.v

The latter form an. image of the incandescent filamentxE. and the light sources I; and 2: areso. arranged with respect .to the lenses 3 on support figthat the imagewould normally appear atlthe axisjof; the helically-coiled, tubular vitreous en:-

velope 1. Of the. flashtube, l.. However, the image;

is .suiiiciently-dispersed by the tubular. envelope 1, which is. usually of glass or quartz, thatsubstantiallythe entire envelope l isluminous at an intensity suchthat acontinuous beam acceptable.

fonfocusing the spotlight on. the subject can-be formed bythe Fresnellens 8 of the spotlight.

Since-the; helical envelope 1; servesas the light.

sourcexduring, focusing and defines the path of; the luminous electric discharge whenthe flashtube is ignitedithe continuous beam projected for focusing. corresponds much more closely to the flashvbeam thanewhen the. conventional arrangementof a lamp'mounted within the coils of the envelope 1 withits; filament at the axis of. the helixisused. In the'latterarrangenient the filament serves asthe light source and because of its smaller size it, produces aubeam greatly different invspreadand in candlepower distribution. than that producedby-theflashtube i The flashtube I; the. incandescent lamp2, the. condenser-lenses 3 and. the spherical. mirror: 4'

are:fixedly-mounted' on the common support: 6.-

The; latter may be. movablyxmounted in the spotlightchousingx-(notshown) so that the flashtube- [may be'placed invarious positions with respect.

t01the= focusofrthe lensrS to adjust the-spread of the beams projected by the spotlight. Preferably, since the envelope 1 is not completely diffusing but only partially diffusing, the angle of the beam of light from the filament 5 incident on the envelope 1 is equal to or approximately equal to the angle which the spotlight lens 8 sub tends or intercepts at the envelope 1. This has not been shown in the drawing which is schematic as far as concern the positioning of the flashtube 2 with respect to the Fresnel lens 8 and the condensing lens 3. The structure of the fiashtube l, the incandescent lamp 2 and the other elements of the illuminatin system of the spotlight are well known and my invent-ion may be readily understood without a detailed description thereof.

What I claim as new and desire to secure by Letters Patent of the United States is:

1. In a spotlight for photography, in combination, a spotlight lens, a support, a fiashtube mounted on said support and contiguous with the focus of said lens and having a convoluted tubular envelope shaped to form a hollow body, a light source capable of emitting light continuously spaced from said flashtube on said support and lens means on said support and so disposed between said source and said tube as to form normally an image of said source within the hollow body formed by the flashtube envelope, at least one turn of said envelope being in the path of the image-forming radiation so that the said radiation is thereby dispersed whereby the envelope is luminous at an intensity such that a beam of I light having a spread and a candlepower distribution closely approaching that of the light beam produced when the flashtube is ignited and of sufficient intensity for focusing the spotlight is formed by the spotlight lens.

2. In a spotlight for photography, in combination, a spotlight lens, a support, a flashtube mounted on said support and contiguous with the focus of said lens and having a convoluted tubular envelope shaped to form a hollow body, a light source capable of emitting light continuously spaced from said flashtube on said support and lens means on said support and so disposed between said source and said tube as to form normally an image of said source Within the hollow body formed by the flashtube envelope, at least one turn of said envelope being in the path of the image-forming radiation so that the said radiation is thereby dispersed whereby the envelope is luminous at an intensity such that a beam of light having a spread and a candlepower distribution closely approaching that of the light beam produced when the flashtube is ignited and of suf- V ficient intensity for focusing the spotlight is formed by the spotlight lens, said support being movable with respect to said spotlight lens for focusing the spotlight on the subject.

3. In a spotlight for photography, in combination, a spotlight lens, a support, a flashtube mounted on said support and contiguous with the focus of said lens and having a tubular envelope with at least one turn, a light source capable of emitting light continuously spaced from said flashtube on said support and lens means on said support and so interposed between said source and said tube as to form normally an image of said source within said turn, said turn being in the path of the image-forming radiation so that the said radiation is thereby dispersed whereby the envelope is luminous at an intensity such that a beam of light having a spread and a candlepower distribution closely approaching that of the light beam produced when the flashtube is ignited 4 and of suificient intensity for focusing the spotlight is formed by the spotlight lens.

4. In a spotlight for photography, in combination, a spotlight lens, a support, a flashtube mounted on said support and contiguous with the focus of said lens and having a tubular envelope shaped in the form of a helix having spaced turns, an incandescentflamp spaced from said flashtube on said support and lens means on said support and so disposed between said lamp and said tube as to form normally an image of the incandescent filament at the axis of the helix, turns of said envelope being in the path of the image-forming radiation so that the said radiation is thereby dispersed whereby the envelope is luminous at an intensity such that a beam of light having a spread focusing the spotlight is formed by the spotlight lens.

5. In a spotlight for photography, in combination, a spotlight lens, a support, a flashtube mounted on said support and contiguous with the focus of said lens and having a tubular envelope shaped in the form of a helix having spaced turns, an incandescent lamp spaced from said flashtube on said support and lens means on said support and so disposed between said lamp and said tube as to form normally an image of the incandescent filament at the axis of the helix, turns of said envelope being in the path of the image-forming radiation so that the said radiation is thereby dispersed whereby the envelope is luminous at an intensity such that a beam of light having a spread and a candiepower distribution closely approaching that of the light beam produced When the flashtube is ignited and of sufiicient intensity for focusing the spotlight is formed by the spotlight lens,said condensing lens and the spotlight lens subtending approximately equal angles at the envelope of the flashtube.

FRANK E. CARLSONL REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Clarkson May 18, 1943 

